The idea behind recent experiments with narrow band analogue SSTV transmissions is simply an attempt to redefine some common practices among SSTV amateurs. The redefined practices attempt to “fit” SSTV QSOs into the normal operations of the digital radio enthusiasts. PSKers, MFSK operators, and Olivia users are used to navigating a specific section of the bands, and are used to digital rag-chews that exchange signal reports, station info and general operator info (e.g. “been a ham 100 years”). In North America the SSTV enthusiasts have tended to congregate on a couple of frequencies and participate in voice conversations between the sending of pictures. Typical PSKers enjoy QSOs without having to use a microphone. At times, QSOs can be had without disturbing others in the household late at night.
In order for the SSTV signals to be located in the typical PSK31/Olivia/MFSK portions of a band, the SSTV signal must be less than 500 Hz in width. Most common SSTV modes are much wider than this, but lo-and-behold, several hams have recently reminded us that narrow band SSTV has been added to MMSSTV. So now digital radio folks can have SSTV QSOs in the same frequency ranges as their other QSOs. This has a special appeal if you like to use the 30M band. This band, for USA hams, is assigned to CW and Data modes. 30 meter enthusiasts can use narrow SSTV and user “text overlays” to communicate reception reports, QTH, station information, etc.
How these QSOs should be conducted has yet to be firmly established. Some have suggested having the usual PSK/MFSK/DominoEX type QSOs and switching to MMSSTV when a picture needs to be sent. MMSSTV has some interesting abilities where one can actually “keyboard” within the picture. With the concept of “a picture is worth a thousand words” in mind, here is how MMSSTV might be used in narrow mode.